Questions of size and numbers in environmental research on ... · PDF fileQuestions of size and numbers in environmental research on ... Mumbai, India Beaches High ... Hawaiian archipelago

Environ. Chem. 2015, 12, 527-538 ©CSIRO 2015 ©CSIRO 2014 doi:10.1071/EN15012_AC

Page 1 of 34

Supplementary material

Questions of size and numbers in environmental research on microplastics: methodological and conceptual aspects

Montserrat FilellaA,B

AInstitute F.-A. Forel, University of Geneva, Route de Suisse 10, CH-1290 Versoix, Switzerland.

Email: [email protected]

BSCHEMA, Rue Principale 92, L-6990 Rameldange, Luxembourg.

Environ. Chem. 2015 ©CSIRO 2015 doi:10.1071/EN15012_AC

Page 2 of 34

Table S1. Microplastics in aquatic systems. location, type of sample, sampling procedure, initial separation and sample treatment methods, and

identity verification in published studies

Studies are listed in chronological order, starting with the most recent

Reference Location Type of system Type of sample Number of sampling points; number of samplesA

Sampling or initial size separation

Sample treatmentB Verification

Sediments [1] Norderney Island,

Germany Tidal mudflats Drift lines (2) and

dune valley (1), upper 3 cm layer

3; 36 Sieving 1 mm mesh

>1 mm: none

<1 mm: flotation (saturated NaCl, d = 1.2 g cm–3 + NaI, d = 1.8 g cm–3); as described in Nuelle et al.[2]

32 random particles analysed by TD-Pyr-GC/MS, 47% confirmed

[3] Singapore Mangroves Top 3–4 cm at low tide

7; ? No sieving mentioned

Flotation (concentrated saline solution, d = 1.18 g dm–3), addition Tween-80, filtration 0.1 cm and 1.6 μm

‘a representative group of microplastics’ identified by ATR-FTIR’

[4] Atlantic Ocean, Mediterranean Sea, Indian Ocean

Deep-sea sediments (some 12 years old)

~1000 m deep 8: upper 1 cm; 4: 2, 5 cm

12 No sieving mentioned

8 samples: flotation (concentrated NaCl), filtration (size not given)[5]

4 samples: flotation (Ludox-TM 40), centrifugation, filtration 32 μm[6]

FTIR

[7] Portugal coast Beaches Top 2 cm at high tide level

10; not given (3–5 replicates for each location)

Sieving ~3-mm metal mesh

As described in Martins and Sobral[8]

μ-FTIR in some resin pellets


Page 3 of 34




[9] Lake Garda, Italy Lake beaches Top 5 cm 2; 6 No sieving mentioned

Flotation (1.6–1.7 kg dm–3 ZnCl2), filtration 0.3 μm; as described in Imhof et al.[10]

Raman microspectroscopy

[11] Mumbai, India Beaches High-tide mark, top 2 cm

4; 240? Sieving 1 mm Flotation (140 g dm–3 NaCl) No

[12] Near Nakdong estuary, South Korea

Beaches Strandline, upper 5 cm

6; 90? Tyler sieves 5, 1 mm

No

[13] Belgian Continental Shelf

Beaches Upper 5 cm, at the low- and high-water mark

4; 8 Sieving 1 mm Elutriation, sieving 35 μm, flotation (1.6 g cm–3 NaI), filtration 5 μm, as described in Claessens et al.[14]

No

[15] Atlantic Ocean

Mediterranean Sea

Deep-sea sediments (1176–4844 m deep)

Nile deep sea fan

Only top 1 cm of the cores considered

4; 11 Wet sieving 1 mm, then 35-μm mesh

Flotation (1.6 g cm–3 NaI), filtration 0.8 μm

Raman microspectroscopy

[16] Venice Lagoon, Italy Shallow water sediments (<1m depth)

0–5 cm sediments (box-corer)

10; 20 No sieving mentioned

Flotation (120 g dm–3 NaCl), sieving 32 μm, filtration 0.7 μm; as described in Thompson et al.[5]

Surface chemical mapping of filters by μ-FTIR; observation by ESEM-EDS

[17] Lake Geneva, Switzerland

Lake beaches 2, 5-mm sieves Flotation (water) No

[18] East Frisian islands: Spiekeroog, Kachelotplate

Beaches and tidal flats Upper 1 cm 11 (from figure); ?

No sieving mentioned

OM H2O2 digestion, flotation (1.5 g cm–3 ZnCl2), filtration 1.2 μm

No


Page 4 of 34




[19] Ocean Beach, San Diego, California, US

Beaches Upper 1 cm of sand

1; 16? Sieving 2 mm No details No

[20] Hawaiian Archipelago (Kamilo, Waikapuna beaches)

Beaches 25 cm sediment cores


Flotation (1.2 g cm–3 NaCl); brass US sieves (4, 2, 1, 0.5, 0.25 mm)

248 plastic fragments analysed by FTIR

[21] Belgian coast Harbours

Beaches

Coastal shelf

Subtidal sediments

High, subtidal, middle

Subtidal sediments

3; 11

3

6

No sieving mentioned

Flotation (concentrated saline solution), sieving 38-μm mesh; as described in Thompson et al.[5]

‘Particles of each type’ analysed by FTIR

[8] Portugal Beaches Last high tide mark, top 2 cm sand

5 A: No sieving

B: In situ sieving 2.5 × 3.5-mm metal mesh

A: Flotation (140 g dm–3 NaCl), filtration 1 μm

B: ‘plastic set apart from the remained debris’ How?

Some ‘selected’ items analysed by FTIR

[22] Lake Huron, Canada Lake beaches – 7 No sieving mentioned

Air-drying, sonication 45 particles analysed by FTIR

[23] Tamar estuary, UK Strandlines Underlying 3 cm of sediment


Flotation (saturated solution of NaCl); as described in Thompson et al.[5]

FTIR

[24] Boa Viagem, Recife, Brazil

Beach Strandline, upper 2 cm of sand

1; 9 Sieving 1 and 0.5 mm wire cloths

Washing in filtered seawater No


Page 5 of 34




[25] Fernando de Noronha, Equatorial Western Atlantic

Beaches Strandline, upper 2 cm of sand

11; 15 Sieving 1 mm – No

[26] Singapore Beaches 0.5 m away from the ocean tideline; some points top 1 cm; some at 10–11-cm depth


Flotation (1.2 kg dm–3 saline solution), filtration 1.6 μm; as described in Thompson et al.[5]

FTIR analysis for all suspected particles

[27] Hawaiian archipelago Beach High-tide line and bern, top 5.5 cm sand

9; 22 Only particles 1–15 mm retained (nested sieves: 4.75, 2.8, 1 mm)

– Dry sort: none

– Wet sort: cleaning with water

No

[5] Around Plymouth, UK

Beach (sandy intertidal)

Estuarine sediment (intertidal)

Subtidal sediment

Strandline 6; 30 No sieving mentioned

Flotation (1.2 kg dm–3 NaCl), filtration

FTIR

Water

[28] Bay of Calvi, Corsica, Italy

Coastal surface seawater

First 0.2 m of sea surface

1; 38 Floating wp2 net (200-μm mesh)

Plastic particles separated from organic tissue by gravity in graduated cylinders

No


Page 6 of 34




[29] Worldwide open oceans

Surface seawater 141 sites; 3070

Neuston net (200-μm mesh)

Mixed with 0.2-mm-filtered seawater

Raman applied to a random subset of particles (n = 67)

[30] NE Pacific Ocean

Coastal British Columbia, Canada

Subsurface seawater 4.5-m depth 2 cruises; 34

Pumped, (saltwater intake system of the vessel), filtration 5 mm

Cu sieves (250, 125, 62.5 μm), each fraction OM acid digestion (conc HCl), filtration 47 μm

‘Plastics identified according morphological characteristics and physical response features (e.g., response to physical stress)’

[31] Lake Hovsgol, Mongolia

Lake water 9 transects Manta trawl (333-μm mesh)

Tyler sieves (0.355–0.999, 1.00–4.749, >4.75 mm), each fraction OM H2O2 digestion, flotation (1.62 g cm–3 salt water)

No

[32] Portuguese coastal waters (Aveiro, Lisboa, Costa Vicentina, Algarve)


Upper 20 cm of water column except with plankton recorder (25 m deep)

4; 152 Neuston net (280 μm), plankton recorder (335 μm)

Filtration mentioned but no pore size given, just diameter of filter!

μ-FTIR, number of analysed samples not clear

[33] Seto Inland, Japan Coastal surface seawater

4; 15 Neuston net (350 μm)

– μ-FTIR, number of analysed samples not clear

[34] Goiana estuary, Brazil

Estuarine waters Surface and bottom hauls

1; 216 Plankton net (300 μm)

‘Floating plastics’ sieved 45-μm mesh

No


Page 7 of 34




[35] Highly urbanized river, Chicago, US

River water 2; 8 Neuston net (333 μm)

Stacked sieves (2 mm, 350 μm), OM H2O2 digestion, flotation (NaCl)

No

[36] Tamar estuary, England

Estuarine waters Surface water 4?; 36? Manta net (300-μm mesh)

Set of sieves (3 mm, 1 mm, 270 μm) FTIR on 50% of the pieces from each size group

[37] Coastal areas close to Nakdong River, South Korea


SML (150–400 μm) waters

10; 20? SML, bulk water, hand net (50-μm mesh): filtration, manta trawl (330-μm mesh)

SML: filtration 0.75 μm

Bulk water: filtration 1, 0.75 μm

Hand and trawl: sieving 2 mm: >2 mm counted, <2 mm: H2O2 digested, filtered 0.75 μm

All SML: FTIR

Other: only ‘selected’

[38] Yangtze estuary, China

East China Sea

Estuarine and surface seawater

estuary: 1 m deep 1; 7

3; 15

Estuary: pumped, sieving 32 μm

Sea: neuston net (333 μm)

OM H2O2 digestion, flotation (saturated ZnCl2 solution),[18] filtration 1.2 μm

No

[39] Jade System, Southern North Sea

Coastal seawater 20-cm depth 14; 2 replicates

100 mL PE bottles filling, filtration 1.2 μm

In one case: 40-μm sieve, OM H2O2 digestion

No

[40] Laurentian Great Lakes (Erie, Huron, Superior)

Lake surface water 3 lakes; 21 Manta trawl (333-μm net)

Flotation (salt water), Tyler sieves (0.355–0.999, 1.00–4.749, >4.75 mm)

All particles <1 mm analysed by SEM-EDS


Page 8 of 34




[41] South Pacific subtropical gyre

Surface seawater transect; 48 Manta trawl (333-μm net)

Flotation (salt water), Tyler sieves (0.355–0.999, 1.00–4.749, >4.75 mm)

No

[42] Northeast Pacific Ocean

Seawater Surface

Subsurface, max depth 210 m

2 cruises; 147

1 cruise; 119

Manta tow (333-μm mesh

Bongo tow (202-μm mesh)

– Subset (n=557) analysed by FTIR; all confirmed to be plastic

[43] Saint Peter and Saint Paul Archipelago, Equatorial Atlantic

Surface seawater 0–0.6 m from the surface

3; 88 Plankton net (300-μm mesh)

Filtration 0.45 μm No

[44] Waters around Australia

Surface coastal seawater

– 57; 71 Neuston net (335-μm mesh) or Manta net (333-μm mesh)

Flotation (seawater) Random 200 particles analysed by FTIR

[45] North Western Mediterranean Sea

Surface seawater Top 10 cm of the sea surface

40 Manta trawl net (333-μm mesh)

Plastic particles separated from organic tissue by gravity in graduated cylinders

No


Mediterranean Sea

Surface water – 1

2

Manta trawl net (300-μm mesh)

Sieve 5 mm No


Page 9 of 34




[46] Northeast Pacific Ocean: Southeast Bering Sea, off US West coast

Seawater Upper 10–15 cm

~212-m depth

6; 271

4; 324

Nets (505-μm mesh)

– ‘Plastic was confirmed by analyst experience including knowledge of morphological and physical response properties’; when in doubt (21 particles): FTIR

[47] Western North Atlantic Ocean and Caribbean Sea

Surface seawater 22-year data set (1986–2008)

6136 Plankton net tows (335-μm mesh)

– No

[48] Western North Atlantic Ocean

Surface seawater Samples archived from past cruises

11 Neuston tow (335-μm mesh)

– Density measurements (for all) combined with elemental analysis (for 19 particles)

[49] North Pacific Ocean, Kuroshio Current area

Seawater Surface water 7 cruises; 76

Newton net (330-μm mesh)

– No

[26] Singapore’s coast Coastal seawater SML (50–60 μm deep), subsurface layer (1 m deep)

2 × 2; 20 SML: rotating drum sampler Subsurface: pump

Filtration 1.6 μm FTIR


Page 10 of 34




[50] Santa Monica Bay, California, US

Seawater Surface, 5 m depth, near bottom (20 cm from bottom)

2 Manta trawl, bongo net, epibenthic sled. All: 333-μm nets

Flotation (freshwater), Tyler sieves (4.75, 2.80, 1.00, 0.71, 0.50, 0.35 mm)

No

[5] Atlantic Ocean: routes between Aberdeen and Iceland

Archived (since 1960) plankton samples

10-m depth Scrolling 280-μm mesh silkscreen

– Unusual fragments identified using FTIR

[51] Coastal zone near Long Beach, California, US

Surface coastal seawater

Before and after storm

5; 10 Manta trawl (333-μm mesh)

Tyler sieves: 4.75, 2.80, 1.00, 0.70, 0.50, 0.35 mm

No

[52] North Pacific subtropical high

Surface seawater 2 transects; 11

Manta trawl (333-μm mesh)

Flotation (seawater), Tyler sieves (4.76, 2.80, 1.00, 0.71, 0.50, 0.35 mm)

No

[53] North Pacific Ocean Surface seawater 27 Neuston sampler (0.053 mm mesh)

Tyler sieves (1.000, 0.710, 0.500, 0.250, 0.053 mm)

No

[54] North Atlantic: Sargasso Sea, Caribbean, shelf and slope water

Surface seawater >420 Neuston net (333 or 500-μm meshes)

– No

[55] North western Atlantic

Surface seawater 243 (in 3 zones; 305

Neuston net (0.947 mm mesh)

– No


Page 11 of 34




[56] Sargasso Sea Surface seawater –; 11 Neuston net (330-μm mesh)

– No

ANumber of samples information is particularly difficult to extract from publications; probably inaccurate.

Bd, density.


Page 12 of 34

Table S2. Microplastics in aquatic systems. size definition, counting method and results in published studies

Studies are listed in chronological order, starting with the most recent.

Reference System Size definitionA Counting method Actual number of particles countedB

RangeC Particle concentrationB,D Did all samples contain microplastics? Lower

limit Higher limit

Sediments [1] Norderney

Island, Germany (tidal mudflats)

None

Upper limit: sieve

Stereomicroscope (6.5–40×) with camera

<1 mm: 59 Not given 1 mm 1–2 # kg–1 No, <1 mm: 26 out of 36

Fibres: yes

[3] Singapore (mangroves)

Diameter? (diameter written in a figure)

Optical microscope (10×)

Not given 1.6 μm >5000 μm 36.8 # kg–1

Calculation of # in a given size range from % in figure and mean value above possible

Yes

[4] Atlantic Ocean, Mediterranean Sea, Indian Ocean (deep-sea sediments)

None Binocular microscope

Not given 8: unknown

4: 32 μm

Not given 1.4–40 # per 50 mL Yes

[7] Portugal (beaches)

None

Upper limit: sieve

See Martins and Sobral[8]

Not given Not given 3 mm 2397 # m–2 Not said


Page 13 of 34



limit Higher limit

[9] Lake Garda, Italy (beaches)

None Raman microspectroscopy (10–50×)

Not given 0.3 μm >5 μm North shore: 1108 # m–2

South shore: 108 # m–2

Not said, probably yes

[11] Mumbai, India (beaches)

‘length measured to the nearest mm along the longest axis’

Lower limit: sieve

Visual? Not given 1 mm 5 mm 28.8 # m–2 (calculated for 1–5 mm from total plastics = 68.83 # m–2)


[12] South Korea (beaches)

None

Upper, lower: sieve

Visual? Not given 1 mm 5 mm May (before raining season): 8205 # m–2

September (after): 27,606 # m–2


[13] Belgian Continental Shelf (beaches)

None

Upper: sieve

No details given Not given 5 μm 1 mm 13 # kg–1 Yes

[15] Atlantic Ocean (deep-sea sediments), Mediterranean Sea (Nile fan)

‘measurement of both length and width’

Visual inspection; details not given

5

(sizes: 118, 75, 161, 83, 125 μm)

0.8 μm 1 mm – No, found in 3 out of 4 locations


Page 14 of 34



limit Higher limit

[16] Venice Lagoon, Italy (superficial sediments)

None Optical microscope

Not given 0.7 μm Not clear 672–2175 # kg–1 Yes


None

Upper: sieve

Visual, no details given

11 <2 mm 5 mm – Yes

[18] East Frisian islands Spiekeroog, Kachelotplate (beaches and tidal flats)

None Dissecting microscope (80×)

Not given 1.2 μm Not clear Kachelotplate: 0–496 # per 10 g

(granules)

Spiekeroog: 0–38 # per 10 g

(granules)

Tidal flat: 36, 136 # per 10 g (granules)

Not said, apparently not

[19] Ocean Beach, San Diego, California, US (beaches)

None No details given <5 mm: 1668 (calculated from 2453 all plastic items, 68%)

2 mm 50 mm – Not said

[20] Hawaiian Archipelago (beaches)

None

PSD by sieving

Size classification by sieving and weighting

Not given <0.25 mm >4 mm Results in percentage by weight

Not said, apparently yes


Page 15 of 34



limit Higher limit

[21] Belgian coast (harbours, beaches, coastal shelf)

None Binocular microscope

Not given 38 μm 1 mm Means: H: 166.7 # kg–1

B: 92.8 # kg–1

CS: 97.2 # kg–1

Yes

[8] Portugal (beaches)

None

‘plastic pieces classified, counted and weighted, according to Ogi and Fukumoto[57]’

Stereoscopic microscope

<5 mm: 12,637 (calculated from 17,799 all plastic items, 71%)

<1 mm >10 mm 137 # m–2 (calculated for <5 mm from total plastics = 185.1 # m–2, 71%)

Yes

[22] Lake Huron, Canada (beaches)

None No details given 3209 (all sizes included)

Not given Not given Not given, except for the beach with 94 % of the total: 408 # m–2

No, only in 4 out of 7 beaches

[23] Tamar estuary, UK (strandlines)

Maximum diameter

No details given <1 mm: 619 (calculated from 952 all plastic items, 65%)

Not given Not given Not given Not said

[24] Boa Viagem, Recife, Brazil (beach)

None

Sieving

Stereomicroscope 2751 <1 mm 20 mm 0.29 # cm–2 (‘plastics’), 0.01 # cm–2 (pellets)

Yes


Page 16 of 34



limit Higher limit

[25] Fernando de Noronha, Western Atlantic (beaches)

None

Lower: sieve

Material was sieved and weighted’

81 (calculated as 39% of 207 plastic items but microplastics?)

1 mm 5 mm – Debris in 87%

[26] Singapore (beaches)

None Scan with FTIR microscope (1000×) on selected areas of filters

25 1.6 μm Not given E No, 4 out of 26

[27] Hawaiian archipelago

None

Upper, lower, PSD: sieving

No details given 19,100 1 mm 15 mm – Yes

[5] Around Plymouth, UK (beach and estuary)

None Microscope (30×) Not given Not given Not given F No, present in 23 out of 30

Water

[28] Bay of Calvi, Corsica, Italy

None

Net

Binocular microscope

Not given 0.2 mm 5 mm 5.1 # 100 m–2 No, <2 mm: found in 24 out of 38 samples, 2–5 mm: found in 26 out of 38 samples


Page 17 of 34



limit Higher limit

[29] Worldwide open oceans

‘maximum linear length’

Net

Dissecting microscope

7359 (all sizes) 0.2 mm Not given Results in g km–2 for each ocean

88% occurrence of plastic, but microplastic?

[30] NE Pacific Ocean

Coastal British Columbia, CA

‘longest dimension’

PSD by sieving

Stereomicroscope Not given <100 μm (smallest detected: 64.8 μm)

>5000 μm (largest detected: 5810 μm)

2080 # m–3 Yes

[31] Lake Hovsgol, Mongolia

None

Net

PSD by sieving

Light microscope Not given 0.333 mm >4.75 mm <4.75 mm: 16,429 # km–2

(all: 20,264 # km–2)

Yes

[32] Portuguese coastal waters

None

Net

Stereoscopic microscope

684 280, 335 μm, depending on sample

Not given Four sites: 0.002, 0.033, 0.036, 0.014 # m–3

No, only present in 61% of samples

[33] Seto Inland, Japan coastal waters

‘longest length’

Net

Stereomicroscope + camera

991 0.350 mm 30 mm PSD in figures (# m–3 for four sites)

Not said

[34] Goiana estuary, Brazil

None Stereomicroscope (5×) + camera

14,724 0.300 mm 5 mm 26.04 # per 100 m–3 Not said


Page 18 of 34



limit Higher limit

[35] Highly urbanized river, Chicago, US

None

Net


Not given 0.330 mm 2 mm Upstream WWTP: 1.94 # m–3

Downstream WWTP: 17.93 # m–3

Yes

[36] Tamar estuary, England

None

Net

No details given 172

<5 mm: 140

0.300 mm >5 mm – Not said

[37] Coastal areas close to Nakdong River, South Korea

SML: ‘maximum size’

Others: ?

SML: FTIR microscope

Others: dissecting microscope

Not given <50 μm >1000 μm <50–1000 μm: 209 # m–3

(all: 211 # m–3)

Not said

[38] Yangtze estuary, China

East China Sea

None

Sea: net

Dissecting microscope (80×)

Estuary: 1489

Sea: 375 (<5 mm: 342)

32 μm >5 mm Estuary: 4137 # m–3

Sea: 0.167 # m–3

Yes

[39] Jade System, Southern North Sea

None Dissecting microscope (80×)

Not given 1.2 μm Not clear 152 # dm–3 Not present in all samples (% given)


Page 19 of 34



limit Higher limit

[40] Laurentian Great Lakes

None

PSD by sieving


2078 but in 16 sites <20 particles counted/site

0.333 mm >4.75 mm Superior: 5391 # km–2

Huron: 2779 # km–2

Erie: 105,503 # km–2

No, found in 20 out of 21 net tows

[41] South Pacific subtropical gyre

None

PSD by sieving


Not given 0.333 mm >4.75 mm <4.75 mm: 24,498 # km–2

(all: 26,898 # km–2)

No, found in 46 out of 48 net tows


2D surface area and maximum diameter

Net

Dissecting microscope (6–12×), particles digitally imaged (resolution 10.6 μm)

2009: 30 518 (surface) + 324 (subsurface)

2010: 1572 (surface)

Surface: 0.333 mm

Subsurface: 0.202 mm

Not clear Median : 0.448 # m–2 (2009), 0.021 # m–2 (2010)

Not said

[43] Saint Peter and Saint Paul Archipelago, Equatorial Atlantic

None

Net

Stereomicroscope (5×)

71 0.300 mm >5 mm 1 per 100 m3 of seawater No, only 41% of the 88 tows contained at least 1, and a maximum of 8, microplastics


Page 20 of 34



limit Higher limit

[44] Waters around Australia

‘Length’

Net

Visual; no details given

839 0.330 mm 82.6 mm 4256 # km–2 No, 80% of net tows and 93% of net stations had at least one piece

[45] North Western Mediterranean Sea

None

Net

Net

Binocular microscope

4371 0.333 mm 5 mm 0.116 # m–2 No, 90% of the stations yes, 30% of the samples >0.1 # m–2


None Stereomicroscope LG: 107 0.300 mm <5 mm LG: 48,146 # km–2 Yes

Mediterranean Sea

Net MS(1): 1290 MS(2): 126

MS(1): 314,609 # km–2 MS(2): 14,389 # km–2


‘longest dimension’

Net

No details given Not given 0.505 mm >10 mm Range: 0.004–0.19 # m–3 Not present in all samples: – surface: 8.8–84% – subsurface: 1 out of 4 cruises (in this: 28%)


Page 21 of 34



limit Higher limit

[47] Western North Atlantic Ocean and Caribbean Sea

None

Net


64,000 plastic pieces

0.335 mm Not clear Caribbean Sea: 1414 # km–2

Gulf of Maine: 1534 # km–2

29° to 31°N: 20,328 # km–2

62% of all net tows contained detectable amounts of plastic debris

[48] Western North Atlantic Ocean

‘longest edge’

Net


748

(88% <10 mm)

0.335 mm 420 mm – Not said

[49] North Pacific Ocean, Kuroshio Current area

‘longest length’

‘plastic pieces were categorized following Ogi and Fukumoto[57]'

No details given Not given 1 mm >11 mm 1–10 mm: 15,000 # km–2

(all: 174,355 # km–2)

No, plastics detected in 72% stations

[26] Singapore’s coastal water

None No details given 13 1.6 μm Not given – Not found in many sites (7 out of 20; when found, only 1 or 2 particles per sample


Page 22 of 34



limit Higher limit

[50] Santa Monica Bay, California, US

None

Net

PSD by sieving

No details given Not given 0.355 mm >4.75 mm 3.92 # m–3 Yes

[5] Atlantic Ocean

None

Net

No details given Not given 0.280 mm Not given G Not said

[51] Coastal zone near Long Beach, California, US

None

Net

PSD by sieving


Not given 0.355 mm >4.750 mm

7.25 # m–3

(PSD available in %; most in the >4.750 fraction in many cases!)

Yes

[52] North Pacific subtropical high

None

Net

PSD by sieving


27,698 (including >4.760 mm)

0.355 mm >4.760 mm

<4.760 mm: 309,506 # km–2 H

(all: 334,271 # km–2)

Not said

[53] North Pacific Ocean

None

Net

PSD by sieving

Light microscope Not given 0.053 mm >10 mm Results for size classes No, 11 out of 27 locations

[54] North Atlantic: Sargasso Sea, Caribbean, Shelf and slope water

None

Net

No details given Not given 0.330 or 0.500 mm

No upper limit

2100 # km–2 No, present in 68% of all tows


Page 23 of 34



limit Higher limit

[55] Northwestern Atlantic

None

Net


Not given 0.947 mm Not given Results g km–2, mainly in figures

No

[56] Sargasso Sea None

Net


228 0.330 mm Not given, probably largely outside MP range

35,000 # km–2 Yes, but only 1 particle found in 2 samples

AParameter measured, when quoted. BWhen possible, values in the microplastic size range have been calculated; calculated values are given in italic. CInformation difficult to extract: often limits are expressed as ‘>‘ or ‘<‘, lower limits given by filtration of extracted samples (quoted in italic) cannot be taken as real lower limits because of the limitations imposed by the visual counting method. DValues given are mean ones except when ranges or otherwise stated; # = number of particles. E0.16 # kg–1 sediment given in Nor and Obbard[3] for this publication but it is never expressed like it in the original one; the value probably comes from 4 particles being found in one sample (but two in two replicates) of 250 g of sediment. FValues from a digitised figure: Sandy: 0.66 fibre per 50 mL–1 of sediment, estuarine: 2.3 fibre per 50 mL–1 of sediment, subtidal: 5.2 fibre per 50 mL–1 of sediment. GValues from a digitised figure: 1960, 1970: 0.011 fibre m–3, 1980: 0.045 fibre m–3, 1990: 0.035 fibre m–3. H2.23 # m–3 in Moore et al.[51] but only values in # km–2 appear in the original publication.


Page 24 of 34

Table S3. Microplastics in aquatic systems. Particle size distributions in the microplastic size range in published studies

Studies are listed in chronological order, starting with the most recent.

Reference Figure/tableA Size rangesB Data represented (y-axis or table legend)C

Sizing method Number of sites

Sediments

[3] Figure <20, 20–40, 40–60, 60–80, 80–100, 100–500, 500–1000, 1000–2000, 2000–5000, >5000 μm

% distribution of each size class by number of particles

Visual Average

[16] Figure <100, 100–500, >500 μm None (pie) Visual Average

[20] Table <0.25, 0.25–0.5, 0.5–1, 1–2, 2–4, >4 mm Grain size distribution (percent, mm categories)

Sieving By site and core depth

[8] Table

Figure

Figure

<1, 2, 3, 4, 5, 6, 7, 8, 9, 10, >10 mm

Idem

Idem

Average distribution of plastic abundance (items m–2)

Plastic abundance (%)

Plastic weight average (%)

According to Ogi and Fukumoto[57]

By site

Average

Average

[27] Table 1–2.8, 2.8–4.75, >4.75 mm Numbers of plastic pieces Sieving Average

Water

[28] Text 0.2–2, 2–5, 5–10 mm Particles/100 m2 Visual Average

[29] Figure Size limits of the bins followed a 0.1–log series of l. From 220 mm to ~10 cm

Abundance of plastic (items); normalized abundance of plastic (items mm–1)

Visual Average

[30] Table <100 (65), 100–500, 500–1000, >1000 (5810) μm % of total Sieving Average per system

[31] Table 0.333–0.999, 1.000–4.749, >4.75 mm Average microplastic density (particles km–2)

Sieving Average


Page 25 of 34



[33] Figures <0.3–4 mm, each 0.1 mm; 4–10 mm, each 1 mm; >10 mm, each 10 mm

Pieces/m3 Visual Per site

[36] Figure <1 (0.300), 1–3, 3–5, >5 mm Number of pieces Sieving Average

[37] Table <50, 50–100, 100–200, 200–500, 500–1000, >1000 μm

Abundance (particles/L) Visual Average

[38] Table 0.5–1, 1–2.5, 2.5–5, >5 mm Percentage Visual Average (also total values for each site)

[40] Table 0.355– 0.999, 1.00–4.749, >4.75 mm Abundance of plastic particles (counts/km2)

Sieving Average

[41] Table 0.355–0.499, 0.500–0.709, 0.710–0.999, 1.00–2.79, 2.800–4.749, >4.75 mm

Abundance of plastic pieces (items km–2)

Sieving Per type

[42] Figures x-axis: particle area in square centimetres, from 0.001 to 100

Number of particles Visual Average per sampling campaign

[43] Figure 1 (0.330), 1.1–5, >5 mm Total number of microplastics Visual Average

[44] Figure <2.4 (0.330), 2.5–4.9, 5–9.9, >10 mm Number of plastic pieces Visual Average

[46] Figures <1 (0.505), 1–2.5, 2.5–5, 5–10, >10 mm Mean concentration (no/m3) Visual Average per system

[48] Figure 0 to 15 mm, each mm, >15 mm Sample count Visual Average

[49] Table 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, >10 mm Mean abundance (pieces/km2) According to Ogi and Fukumoto[57]

Average

[50] Table 0.355–0.499, 0.500–0.709, 0.710–0.999, 1.000–2.799, 2.800–4.749, >4.750 mm

Percentage density Sieving Average


Page 26 of 34



[51] Table 0.355–0.499, 0.500–0.709, 0.710–0.999, 1.000–2.799, 2.800–4.749, >4.750 mm

Percentage of each debris Sieving Per station

[52] Table 0.355–0.499, 0.500–0.709, 0.710–0.999, 1.000–2.799, 2.800–4.759, >4.760 mm

Abundance (pieces km2) Sieving Average

[53] Figures 0.053, 0.250, 0.500, 0.710, 10 mm Normalized density (= density for each size class divided by the width of that size class), objects km–2 mm–1

Sieving Average

AValues in figures digitised with http://arohatgi.info/WebPlotDigitizer/app/. BIn bold, the size classes that ‘can be used’, i.e. ‘not open’ and in the microplastic size range; values in italic in parentheses: size limit according to sampling procedure or other information given in the article. CThe exact text in the publication is quoted here.


Page 27 of 34

Fig. S1. Examples of variation of the shape factor (SF = 4π area/perimeter) of geometric objects. Reproduced

with permission from Mavrocordatos et al.[58]

Fig. S2. Schematic illustration of dimensions of a particle and its equivalent sieve diameter.


Page 28 of 34

Fig. S3. Different types of representation for the same particle size distribution. Conditions: spherical particles

following a power-law distribution with β = 4, total mass: 0.5 mg dm–3, particle density: 3 × 10–12 g μm–3.


Page 29 of 34

List of abbreviations

ATR- FTIR, attenuated total reflectance–Fourier transform infrared

β, slope of a power law distribution (n(dp) = (ΔN/Δdp) = Adp–β) where ΔN is the number of

particles with a diameter in the size interval Δdp per unit volume of fluid.

d, density

DT-Pyr-GC/MS, thermal desorption pyrolysis gas chromatography mass spectrometry

ESEM-EDS, environmental scanning electron microscopy–energy dispersive spectroscopy

FTIR, Fourier transform infrared

OM, organic matter

PE, polyethylene

PSD, particle size distribution

SEM, scanning electron microscopy

SF, shape factor

SML, surface microlayer

WWTP, waste water treatment plant


Page 30 of 34

References [1] J. H. Dekiff, D. Remy, J. Klasmeier, E. Fries, Occurrence and spatial distribution of microplastics in

sediments from Norderney. Environ. Pollut. 2014, 186, 248. doi:10.1016/j.envpol.2013.11.019

[2] M.-T. Nuelle, J. H. Dekiff, D. Remy, E. Fries, A new analytical approach for monitoring microplastics

in marine sediments. Environ. Pollut. 2014, 184, 161. doi:10.1016/j.envpol.2013.07.027

[3] N. H. M. Nor, J. P. Obbard, Microplastics in Singapore’s coastal mangrove ecosystems. Mar. Pollut.

Bull. 2014, 79, 278. doi:10.1016/j.marpolbul.2013.11.025

[4] L. C. Woodall, A. Sanchez-Vidal, M. Canals, G. L. J. Paterson, R. Coppock, V. Sleight, A. Calafat, A.

D. Rogers, B. E. Narayanaswamy, R. C. Thompson, The deep sea is a major sink for microplastic debris.

Roy. Soc. Open Sci. 2014, 1, 140317. doi:10.1098/rsos.140317

[5] R. C. Thompson, Y. Olsen, R. P. Mitchell, A. Davis, S. J. Rowland, A. W. G. John, D. McGonigle, A.

E. Russell, Lost at sea: Where is all the plastic? Science 2004, 304, 838. doi:10.1126/science.1094559

[6] B. S. Griffiths, B. Boag, R. Neilson, L. Palmer, The use of colloidal silica to extract nematodes from

small samples of soil or sediment. Nematologica 1990, 36, 465. doi:10.1163/002925990X00437

[7] J. C. Antunes, J. G. L. Frias, A. C. Micaelo, P. Sobral, Resin pellets from beaches of the Portuguese

coast and adsorbed persistent organic pollutants. Estuar. Coast. Shelf Sci. 2013, 130, 62.

doi:10.1016/j.ecss.2013.06.016

[8] J. Martins, P. Sobral, Plastic marine debris on the Portuguese coastline: A matter of size? Mar. Pollut.

Bull. 2011, 62, 2649. doi:10.1016/j.marpolbul.2011.09.028

[9] H. K. Imhof, N. P. Ivleva, J. Schmid, R. Niessner, C. Laforsch, Contamination of beach sediments of a

subalpine lake with microplastic particles. Curr. Biol. 2013, 23, R867. doi:10.1016/j.cub.2013.09.001

[10] H. K. Imhof, J. Schmid, R. Niessner, N. P. Ivleva, C. Laforsch, A novel, highly efficient method for the

separation and quantification of plastic particles in sediments of aquatic environments. Limnol. Oceanogr.

Methods 2012, 10, 524.

[11] H. B. Jayasiri, C. S. Purushothaman, A. Vennila, Quantitative analysis of plastic debris on recreational

beaches in Mumbai, India. Mar. Pollut. Bull. 2013, 77, 107. doi:10.1016/j.marpolbul.2013.10.024

[12] J. Lee, S. Hong, Y. K. Song, S. H. Hong, Y. C. Jang, M. Jang, N. W. Heo, G. M. Han, M. J. Lee, D.

Kang, W. J. Shim, Relationships among the abundances of plastic debris in different size classes on beaches

in South Korea. Mar. Pollut. Bull. 2013, 77, 349. doi:10.1016/j.marpolbul.2013.08.013

[13] L. Van Cauwenberghe, M. Claessens, M. B. Vandegehuchte, J. Mees, C. R. Janssen, Assessment of

marine debris on the Belgian Continental Shelf. Mar. Pollut. Bull. 2013, 73, 161.

doi:10.1016/j.marpolbul.2013.05.026

[14] M. Claessens, L. Van Cauwenberghe, M. B. Vandegehuchte, C. R. Janssen, New techniques for the

detection of microplastics in sediments and field collected organisms. Mar. Pollut. Bull. 2013, 70, 227.

doi:10.1016/j.marpolbul.2013.03.009

http://dx.doi.org/10.1016/j.envpol.2013.11.019


http://dx.doi.org/10.1016/j.marpolbul.2013.11.025

http://dx.doi.org/10.1098/rsos.140317

http://dx.doi.org/10.1126/science.1094559

http://dx.doi.org/10.1163/002925990X00437

http://dx.doi.org/10.1016/j.ecss.2013.06.016


http://dx.doi.org/10.1016/j.cub.2013.09.001






Page 31 of 34

[15] L. Van Cauwenberghe, A. Vanreusel, J. Mees, C. R. Janssen, Microplastic pollution in deep-sea

sediments. Environ. Pollut. 2013, 182, 495. doi:10.1016/j.envpol.2013.08.013

[16] A. Vianello, A. Boldrin, P. Guerriero, V. Moschino, R. Rella, A. Sturaro, L. Da Ros, Microplastic

particles in sediments of Lagoon of Venice, Italy: First observations on occurrence, spatial patterns and

identification. Estuar. Coast. Shelf Sci. 2013, 130, 54. doi:10.1016/j.ecss.2013.03.022

[17] F. Faure, M. Corbaz, H. Baecher, L. F. De Alencastro, Pollution due to plastics and microplastics in

Lake Geneva and in the Mediterranean Sea. Arch. Sci. 2012, 65, 157.

[18] G. Liebezeit, F. Dubaish, Microplastics in beaches of the East Frisian Islands Spiekeroog and

Kachelotplate. Bull. Environ. Contam. Toxicol. 2012, 89, 213. doi:10.1007/s00128-012-0642-7

[19] A. Van, C. M. Rochman, E. M. Flores, K. L. Hill, E. Vargas, S. A. Vargas, E. Hoh, Persistent organic

pollutants in plastic marine debris found on beaches in San Diego, California. Chemosphere 2012, 86, 258.

doi:10.1016/j.chemosphere.2011.09.039

[20] H. S. Carson, S. L. Colbert, M. J. Kaylor, K. J. McDermid, Small plastic debris changes water

movement and heat transfer through beach sediments. Mar. Pollut. Bull. 2011, 62, 1708.

doi:10.1016/j.marpolbul.2011.05.032

[21] M. Claessens, S. De Meester, L. Van Landuyt, K. De Clerck, C. R. Janssen, Occurrence and

distribution of microplastics in marine sediments along the Belgian coast. Mar. Pollut. Bull. 2011, 62, 2199.

doi:10.1016/j.marpolbul.2011.06.030

[22] M. Zbyszewski, P. Corcoran, Distribution and degradation of fresh water plastic particles along the

beaches of Lake Huron, Canada. Water Air Soil Pollut. 2011, 220, 365. doi:10.1007/s11270-011-0760-6

[23] M. A. Browne, T. S. Galloway, R. C. Thompson, Spatial patterns of plastic debris along estuarine

shorelines. Environ. Sci. Technol. 2010, 44, 3404. doi:10.1021/es903784e

[24] M. F. Costa, J. A. Ivar do Sul, J. S. Silva-Cavalcanti, M. C. B. Araujo, A. Spengler, P. S. Tourinho, On

the importance of size of plastic fragments and pellets on the strandline: a snapshot of a Brazilian beach.

Environ. Monit. Assess. 2010, 168, 299. doi:10.1007/s10661-009-1113-4

[25] J. A. Ivar do Sul, A. Spengler, M. F. Costa, Here, there and everywhere. Small plastic fragments and

pellets on beaches of Fernando de Noronha (equatorial western Atlantic). Mar. Pollut. Bull. 2009, 58, 1236.

doi:10.1016/j.marpolbul.2009.05.004

[26] K. L. Ng, J. P. Obbard, Prevalence of microplastics in Singapore’s coastal marine environment. Mar.

Pollut. Bull. 2006, 52, 761. doi:10.1016/j.marpolbul.2005.11.017

[27] K. J. McDermid, T. L. McMullen, Quantitative analysis of small-plastic debris on beaches in the

Hawaiian archipelago. Mar. Pollut. Bull. 2004, 48, 790. doi:10.1016/j.marpolbul.2003.10.017

[28] A. Collignon, J.-H. Hecq, F. Galgani, F. Collard, A. Goffart, Annual variation in neustonic micro- and

meso-plastic particles and zooplankton in the Bay of Calvi (Mediterranean-Corsica). Mar. Pollut. Bull. 2014,

79, 293. doi:10.1016/j.marpolbul.2013.11.023


http://dx.doi.org/10.1016/j.ecss.2013.03.022

http://dx.doi.org/10.1007/s00128-012-0642-7

http://dx.doi.org/10.1016/j.chemosphere.2011.09.039



http://dx.doi.org/10.1007/s11270-011-0760-6

http://dx.doi.org/10.1021/es903784e

http://dx.doi.org/10.1007/s10661-009-1113-4






Page 32 of 34

[29] A. Cozar, F. Echevarria, J. I. Gonzalez-Gordillo, X. Irigoien, B. Ubeda, S. Hernandez-Leon, A. T.

Palma, S. Navarro, J. García-de-Lomas, A. Ruiz, M. L. Fernández-de-Puelles, C. M. Duarte, Plastic debris in

the open ocean. Proc. Natl. Acad. Sci. USA 2014, 111, 10239. doi:10.1073/pnas.1314705111

[30] J.-P. W. Desforges, M. Galbraith, N. Dangerfield, P. S. Ross, Widespread distribution of microplastics

in subsurface seawater in the NE Pacific Ocean. Mar. Pollut. Bull. 2014, 79, 94.

doi:10.1016/j.marpolbul.2013.12.035

[31] C. M. Free, O. P. Jensen, S. A. Mason, M. Eriksen, N. J. Williamson, B. Boldgiv, High-levels of

microplastic pollution in a large, remote, mountain lake. Mar. Pollut. Bull. 2014, 85, 156.

doi:10.1016/j.marpolbul.2014.06.001

[32] J. P. G. L. Frias, V. Otero, P. Sobral, Evidence of microplastics in samples of zooplankton from

Portuguese coastal waters. Mar. Environ. Res. 2014, 95, 89. doi:10.1016/j.marenvres.2014.01.001

[33] A. Isobe, K. Kubo, Y. Kamura, S. i. Kako, E. Nakashima, N. Fujii, Selective transport of microplastics

and mesoplastics by drifting in coastal waters. Mar. Pollut. Bull. 2014, 48, 11863.

doi:10.1016/j.marpolbul.2014.09.041

[34] A. R. A. Lima, M. F. Costa, M. Barletta, Distribution patterns of microplastics within the plankton of a

tropical estuary. Environ. Res. 2014, 132, 146. doi:10.1016/j.envres.2014.03.031

[35] A. McCormick, T. Hoellein, S. A. Mason, J. Schluep, J. J. Kelly, Microplastic is an abundant and

distinct microbial habitat in an urban river. Environ. Sci. Technol. 2014, 89, 324. doi:10.1021/es503610r

[36] S. S. Sadri, R. C. Thompson, On the quantity and composition of floating plastic debris entering and

leaving the Tamar Estuary, Southwest England. Mar. Pollut. Bull. 2014, 81, 55.

doi:10.1016/j.marpolbul.2014.02.020

[37] Y. K. Song, S. H. Hong, M. Jang, J. H. Kang, O. Y. Kwon, G. M. Han, W. J. Shim, Large

accumulation of micro-sized synthetic polymer particles in the sea surface microlayer. Environ. Sci. Technol.

2014, 48, 9014. doi:10.1021/es501757s

[38] S. Zhao, L. Zhu, T. Wang, D. Li, Suspended microplastics in the surface water of the Yangtze Estuary

System, China: First observations on occurrence, distribution. Mar. Pollut. Bull. 2014, 86, 562.

doi:10.1016/j.marpolbul.2014.06.032

[39] F. Dubaish, G. Liebezeit, Suspended microplastics and black carbon particles in the Jade System,

Southern North Sea. Water Air Soil Pollut. 2013, 224, 13.

[40] M. Eriksen, S. Mason, S. Wilson, C. Box, A. Zellers, W. Edwards, H. Farley, S. Amato, Microplastic

pollution in the surface waters of the Laurentian Great Lakes. Mar. Pollut. Bull. 2013, 77, 177.

doi:10.1016/j.marpolbul.2013.10.007

[41] M. Eriksen, N. Maximenko, M. Thiel, A. Cummins, G. Lattin, S. Wilson, J. Hafner, A. Zellers, S.

Rifman, Plastic pollution in the South Pacific subtropical gyre. Mar. Pollut. Bull. 2013, 68, 71.

doi:10.1016/j.marpolbul.2012.12.021

http://dx.doi.org/10.1073/pnas.1314705111



http://dx.doi.org/10.1016/j.marenvres.2014.01.001


http://dx.doi.org/10.1016/j.envres.2014.03.031

http://dx.doi.org/10.1021/es503610r


http://dx.doi.org/10.1021/es501757s





Page 33 of 34

[42] M. C. Goldstein, A. J. Titmus, M. Ford, Scales of spatial heterogeneity of plastic marine debris in the

Northeast Pacific Ocean. PLOS One 2013, 8, e80020. doi:10.1371/journal.pone.0080020

[43] J. A. Ivar do Sul, M. F. Costa, M. Barletta, F. J. A. Cysneiros, Pelagic microplastics around an

archipelago of the Equatorial Atlantic. Mar. Pollut. Bull. 2013, 75, 305. doi:10.1016/j.marpolbul.2013.07.040

[44] J. Reisser, J. Shaw, C. Wilcox, B. D. Hardesty, M. Proietti, M. Thums, C. Pattiaratchi, Marine plastic

pollution in waters around Australia: Characteristics, concentrations, and pathways. PLOS One 2013, 8,

e80466. doi:10.1371/journal.pone.0080466

[45] A. Collignon, J.-H. Hecq, F. Galgani, P. Voisin, F. Collard, A. Goffart, Neustonic microplastic and

zooplankton in the North Western Mediterranean Sea. Mar. Pollut. Bull. 2012, 64, 861.

doi:10.1016/j.marpolbul.2012.01.011

[46] M. J. Doyle, W. Watson, N. M. Bowlin, S. B. Sheavly, Plastic particles in coastal pelagic ecosystems

of the Northeast Pacific ocean. Mar. Environ. Res. 2011, 71, 41. doi:10.1016/j.marenvres.2010.10.001

[47] K. L. Law, S. Morét-Ferguson, N. A. Maximenko, G. Proskurowski, E. E. Peacock, J. Hafner, C. M.

Reddy, Plastic accumulation in the North Atlantic Subtropical Gyre. Science 2010, 329, 1185.

doi:10.1126/science.1192321

[48] S. K. Morét-Ferguson, G. Lavender Law, E. K. Proskurowski, E. E. Murphy, C. M. Peacock, Reddy.

The size, mass, and composition of plastic debris in the western North Atlantic Ocean. Mar. Pollut. Bull.

2010, 60, 1873. doi:10.1016/j.marpolbul.2010.07.020

[49] R. Yamashita, A. Tanimura, Floating plastic in the Kuroshio current area, Western North Pacific

Ocean. Mar. Pollut. Bull. 2007, 54, 485. doi:10.1016/j.marpolbul.2006.11.012

[50] G. L. Lattin, C. J. Moore, A. F. Zellers, S. L. Moore, S. B. Weisberg, A comparison of neustonic

plastic and zooplankton at different depths near the southern California shore. Mar. Pollut. Bull. 2004, 49,

291. doi:10.1016/j.marpolbul.2004.01.020

[51] C. J. Moore, S. L. Moore, S. B. Weisberg, G. W. Lattin, A. F. Zellers, A comparison of neustonic

plastic and zooplankton abundance in Southern California’s coastal waters. Mar. Pollut. Bull. 2002, 44, 1035.

doi:10.1016/S0025-326X(02)00150-9

[52] C. J. Moore, S. L. Moore, K. Leecaster, S. B. Weisberg, A comparison of plastic and plankton in the

North Pacific Central Gyre. Mar. Pollut. Bull. 2001, 42, 1297. doi:10.1016/S0025-326X(01)00114-X

[53] D. G. Shaw, R. H. Day, Colour- and form-dependent loss of plastic micro-debris from the North

Pacific Ocean. Mar. Pollut. Bull. 1994, 28, 39. doi:10.1016/0025-326X(94)90184-8

[54] R. J. Wilber, Plastic in the North Atlantic. Oceanus 1987, 30, 61.

[55] J. B. J. Colton, F. D. Knapp, B. R. Burns, Plastic particles in surface waters of the Northwest Atlantic.

Science 1974, 185, 491. doi:10.1126/science.185.4150.491

[56] E. J. Carpenter, K. L. Smith, Plastics on the Sargasso Sea surface. Sci. Total Environ. 1972, 178, 1240.

http://dx.doi.org/10.1371/journal.pone.0080020


http://dx.doi.org/10.1371/journal.pone.0080466


http://dx.doi.org/10.1016/j.marenvres.2010.10.001

http://dx.doi.org/10.1126/science.1192321




http://dx.doi.org/10.1016/S0025-326X(02)00150-9

http://dx.doi.org/10.1016/S0025-326X(01)00114-X

http://dx.doi.org/10.1016/0025-326X(94)90184-8

http://dx.doi.org/10.1126/science.185.4150.491


Page 34 of 34

[57] H. Ogi, Y. Fukumoto, A sorting method for small plastic debris floating on the sea surface and stranded

on sandy beaches. Bull. Fac. Fish. Hokkaido Univ. 2000, 51, 71.

[58] D. Mavrocordatos, D. Perret, G. G. Leppard, in Environmental Colloids and Particles: Behaviour,

Separation and Characterisation (Eds K. J. Wilkinson, J. R. Lead) 2007, pp. 345–404 (Wiley: New York).

Documents

Questions of size and numbers in environmental research on ... · PDF fileQuestions of size and numbers in environmental research on ... Mumbai, India Beaches High ... Hawaiian archipelago